This module only allows for loading a configuration file, not saving. Providing a filename is therefore always required.

Consider that RFE #1. It should support saving. A config file class that only allows for loading is missing a rather important feature if you want the config file to be manipulated by software (such as a GUI or web interface or command line) rather than by text editors. You won't see many config modules in other languages neglect to implement a save feature. It's just not done. CPAN has a few holes in that sort of logic here and there, mainly because it's community supported -- that's ok -- but I'd rather see the signal to noise ratio improved by including core features where applicable.